Approximately 16 million Americans have diabetes and must regularly monitor their blood sugar levels. Kits for assaying blood glucose concentration at home came onto the market approximately 20 years ago and have replaced urine testing as the preferred method for assessing how well a patient's diabetes is being controlled. The kits typically require that a patient puncture a finger with a lancet to obtain a sample for testing. These procedures may be performed several times a day and, due to the high concentration of pain receptors in the fingertips, cause considerable discomfort.
One method of alleviating pain that has been used in other contexts has involved delivering mild pulses of electricity across electrodes taped to a patient's skin (see, e.g., U.S. Pat. No. 4,147,171). The pulses are applied in the region of a patient's body where pain is occurring and appear to interfere with the neuronal transmission of pain signals. The technique has been termed “transcutaneous electrical nerve stimulation” (TENS) and devices for controlling pain using the technique are currently being marketed by several companies, including 3M, American Imex and EMPI. Improvements in TENS technology have generally involved altering the characteristics of the electrical impulses delivered (see, e.g., U.S. Pat. Nos. 4,431,002; 5,109,847; 3,902,50; 5,350,414; 5,069,211; 4,989,605; and 5,052,391) and in miniaturizing devices to make them more portable or more comfortable for use by patients (see, e.g., U.S. Pat. Nos. 5,397,338; 6,445,955; and 6,023,642). A TENS device that could be conveniently used by diabetic patients to reduce the pain that they experience in monitoring blood sugar levels could significantly improve the quality of life for these patients.